珠江口黑鲷海捕群体与不同养殖群体的形态差异比较

为探明珠江口黑鲷海捕苗种与人工繁殖苗种间的形态差异,作者采用3种多元统计分析和方差分析方法,对采集自珠江口两岸的海捕黑鲷(Acanthopagrusschlegelii)苗种与2个繁殖场的人工繁殖苗种进行形态差异比较,比较了不同样品组的外部形态特征差异。可量性状主成分分析结果表明,前2项主成分的累计贡献率为89.90%,聚类分析结果表明汕头苗场(ST)样品组与另外3个样品组距离最远,判别分析结果同样显示以对该样品组判别准确率最高;可数性状单因素方差分析结果表明,样品组间背鳍鳍条数、鳃耙数、椎骨数存在显著性差异(P0.05)。主成分分析、聚类分析、判别分析和单因素方差分析从不同角度反映了样品组间的形态差异,各分析方法获得结论基本类似,相互印证。该研究结果显示,采集自不同繁殖场的黑鲷苗种与珠江口海域野生苗种存在一定的形态差异,但没有证据显示这种差异已导致黑鲷野生和养殖群体间明显的形态分化。

Comparison of Acanthopagrus schlegelii morphological differences between marine fishing population and the different breeding populations in the Pearl River Estuary

To explore the morphological differences of Acanthopagrus schlegelii between the captured samples in Pearl River Estuary and aquatic seedling samples, we statistically compared morphological differences of four A. schlegelii juvenile fish samples between these captured in both sides of the Pearl River Estuary and two aquatic seedling fields in hierarchical cluster analysis, principal component analysis, discriminatory analysis, and one-way ANOVA analysis. Principal component analysis results showed that the cumulative contribution of the first 2 principal components was 89.90%. The hierarchical cluster analysis results showed that the most marked morphological differences displayed between group ST (Shantou seedling field) and the other 3 samples. Discriminant analysis results also showed the highest discriminant accuracy rate of group ST (Shantou seedlings field). The results of One-way ANOVA analysis with meristic characters showed that there were significant differences between four groups on dorsal fin spine, girll raler, vete brate (P<0.05). All results of these statistical analyses reveal the morphological differences between the four samples from different aspects, which are similar and corroborated each other. These findings show that there are some morphological variation of A. schlegelii juvenile fish captured from different aquatic seedling field and the uncultivated group. However, no evidence suggests that these difference has led to significant morphological differentiation between the wild and cultured A. schlegelii populations.